src/glsl/lower_vector_derefs.cpp

   1 /*
   2  * Copyright © 2013 Intel Corporation
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  21  * DEALINGS IN THE SOFTWARE.
  22  */
  23 #include "ir.h"
  24 #include "ir_builder.h"
  25 #include "ir_rvalue_visitor.h"
  26 #include "ir_optimization.h"
  27
  28 using namespace ir_builder;
  29
  30 namespace {
  31
  32 class vector_deref_visitor : public ir_rvalue_enter_visitor {
  33 public:
  34    vector_deref_visitor()
  35       : progress(false)
  36    {
  37    }
  38
  39    virtual ~vector_deref_visitor()
  40    {
  41    }
  42
  43    virtual void handle_rvalue(ir_rvalue **rv);
  44    virtual ir_visitor_status visit_enter(ir_assignment *ir);
  45
  46    bool progress;
  47 };
  48
  49 } /* anonymous namespace */
  50
  51 ir_visitor_status
  52 vector_deref_visitor::visit_enter(ir_assignment *ir)
  53 {
  54    if (!ir->lhs || ir->lhs->ir_type != ir_type_dereference_array)
  55       return ir_rvalue_enter_visitor::visit_enter(ir);
  56
  57    ir_dereference_array *const deref = (ir_dereference_array *) ir->lhs;
  58    if (!deref->array->type->is_vector())
  59       return ir_rvalue_enter_visitor::visit_enter(ir);
  60
  61    ir_dereference *const new_lhs = (ir_dereference *) deref->array;
  62    ir->set_lhs(new_lhs);
  63
  64    ir_constant *old_index_constant = deref->array_index->constant_expression_value();
  65    void *mem_ctx = ralloc_parent(ir);
  66    if (!old_index_constant) {
  67       ir->rhs = new(mem_ctx) ir_expression(ir_triop_vector_insert,
  68                                            new_lhs->type,
  69                                            new_lhs->clone(mem_ctx, NULL),
  70                                            ir->rhs,
  71                                            deref->array_index);
  72       ir->write_mask = (1 << new_lhs->type->vector_elements) - 1;
  73    } else {
  74       ir->write_mask = 1 << old_index_constant->get_int_component(0);
  75    }
  76
  77    return ir_rvalue_enter_visitor::visit_enter(ir);
  78 }
  79
  80 void
  81 vector_deref_visitor::handle_rvalue(ir_rvalue **rv)
  82 {
  83    if (*rv == NULL || (*rv)->ir_type != ir_type_dereference_array)
  84       return;
  85
  86    ir_dereference_array *const deref = (ir_dereference_array *) *rv;
  87    if (!deref->array->type->is_vector())
  88       return;
  89
  90    void *mem_ctx = ralloc_parent(deref);
  91    *rv = new(mem_ctx) ir_expression(ir_binop_vector_extract,
  92                                     deref->array,
  93                                     deref->array_index);
  94 }
  95
  96 bool
  97 lower_vector_derefs(gl_shader *shader)
  98 {
  99    vector_deref_visitor v;
 100
 101    visit_list_elements(&v, shader->ir);
 102
 103    return v.progress;
 104 }